1. Field of the Invention
This invention relates generally to earth-working equipment and particularly to a detachably mounted ripper tool for a conventional excavator type bucket.
2. History of the Prior Art
When utilizing conventional backhoe type equipment, it is not uncommon that the excavation operations are complicated by poor soil conditions. Often the ground to be worked is frozen, rocky, or simply extremely well packed or dense. In such instances, some means must be provided to break up the hardened earthen material before a backhoe bucket or scoop can be used to excavate the same.
Heretofore, numerous cutting and ripping attachments have been designed either for use with or attachment to backhoe or other excavator buckets so as to enable such equipment to be used when poor soil conditions are encountered. Some of these attachments may be mounted directly on the bucket or scoop to break, cut, or rip through hardened material. The advantage of such a direct mounting is that the excavation operation may, for the most part, be carried out simultaneously with the ground breaking operation.
In order to concentrate the penetrating or earth breaking force of the bucket and ripper combination, many prior art devices utilize a single or primary ripper tooth as the earth breaking implement. Normally the ripper tooth is of a greater dimension than the earth working teeth which are carried or mounted on the bucket, being of a sufficient length to permit the ripper to extend beyond the cutting or digging edge of the bucket, and frequently greater in cross-sectional width or depth dimensions to provide increased structural strength.
Due to the localization of stresses on the ripper tooth as it penetrates through the hardened ground, it is not only necessary that the ripper be strong, but it is also important that its connection to the bucket be secure. However, because it is not always necessary to use the ripper attachment, the mounting should be simplistic enough to permit the equipment operator to quickly and easily attach or remove the assembly to or from the bucket respectively.
To simplify the mounting, several prior art devices utilize a single pivoted connector by which the ripper is attached to one portion of the bucket while a hooked, cupped, or friction type fit is used to support another portion of the ripper shank. In this manner, the ripper is quickly attached to the bucket using a single bolt or pin. However, such mountings have not provided for a complete or uniform distribution of the stresses across the bucket structure. Rather, the bulk of the stresses will frequently be imparted to a weaker structural member than the ripper tooth itself, as for instance, to the mounting pin or bolt or perhaps a portion of the edge of the bucket or bucket tooth.
Another problem often encountered when using ripper attachments has been that, in excavating trenches or ditches, the dirt walls are left rough and uneven. Such edging problems, although to a lesser degree, are frequently encountered when using the bucket alone. Therefore, side cutters, such as those disclosed in U.S. Pat. No. 3,748,762 to Tarrant, may be required on some types of buckets during normal trenching operations. However, in order to correct such a problem when using ripper attachments, some means must be provided along both sides of the bucket to obtain a relatively even cut without greatly reducing the earth penetrating force being concentrated at a relatively localized area of ground by the earth breaking ripper tooth.
Some examples of the prior art include U.S. Pat. Nos. 2,783,558 to Morgan; 2,838,856 to Buisse; 3,039,210 to Slaughter; 3,097,439 to Calkin; and 3,724,899 to Clark.